Vehicles having an automatic transmission and electrical vehicle having a electric motor are set up with several shift lever positions including at least a parking position, a reverse position and a drive position. A shift-locking device is provided for preventing the vehicle from suddenly starting when the shift lever is in the drive position or reverse position.
One known form of an electrical shift-locking device is described in the new model manual for the Toyota Avalon issued in May 9, 1999, page 2-17. This electrical shift-locking device is operated by a solenoid and is disposed inside a shift lever device. The shift-locking device controls a solenoid to input an electrical signal upon application of the brake pedal and an electrical signal upon operation of the ignition key to the start position. Accordingly, the shift lever cannot not be shifted from the parking position unless the brake pedal is applied and the ignition key is operated to the start position.
A mechanical shift-locking device is described in Japanese Laid-Open application No. Hei 6-265011. This mechanical shift-locking device is operated by a cable which is connected to a key cylinder of an ignition key and is disposed inside of a shift lever device. Accordingly, the shift lever cannot shift from the parking position unless the brake pedal is applied and the ignition key is operated to the start position.
Another structural mechanical shift-locking device is described in "Die neue A-Klasse von Dimler-Benz (Senderausgabe ATZ and MTZ)". This mechanical shift-locking device is operated by a cable and is attached to a parking control device connected to a manual shaft which rotates in correspondence to the shift lever. The parking control device has a detent mechanism for maintaining the rotated position of the manual shaft.
However, the electrical shift-locking device mentioned above is expensive because it requires relatively high priced elements, for example a computer, a solenoid and the like. Furthermore, this device requires a manual shift-locking release device distinguishable from the electrical shift-locking device so that it is possible to release the shift-locking when an electrical element becomes broken or unoperational. The need for this mechanical shift-locking device makes the device as a whole more expensive. Also, that the electrical shift-locking device can be released from shift-locking inside the vehicle has an effect of reducing the prevention of vehicle theft.
The first mechanical shift-locking device mentioned above is cheaper than the electrical shift-locking device. However, the mechanical shift-locking device can release the shift-locking inside the vehicle and so the effect of preventing vehicle theft is once again reduced.
The other mechanical shift-locking device is once again cheaper than the electrical shift-locking device and, in this case, the mechanical shift-locking device cannot release the shift-locking inside the vehicle. Thus, the effect of preventing vehicle theft is increased. However, because the shift-locking device is attached to the parking control device, it requires a relatively large space to install the device. Accordingly, the size of the transmission is enlarged.
In light of the foregoing, a need exists for a shift-locking device for a vehicle transmission that is not as susceptible to the problems mentioned above.
A need also exists for a shift-locking device for a vehicle transmission that is low in cost, is able to increase vehicle theft prevention, and results in a compact transmission.